1. Field of the Invention
The dental casting apparatus and method of the present invention involves a new apparatus and method for making one or more dies for crowns, bridges, and false teeth.
2. Background Art
The conventional system used in the United States for making dies for teeth is labor intensive. Initially, an impression of the patient's jaw is made and the impression is allowed to harden. The impression is then filled with wet stone, which must also be allowed to harden, forming a casting. The casting is then removed from the impression, a flat bottom portion and an outside wall for the casting are both formed by grinding out excess stone. An inside wall is formed for the casting by applying a lathe to remove excess stone. The casting is then cleaned by using pressurized air, and the casting is allowed to dry.
The individual pins are then drilled in the casting with a pindex machine: index pins are inserted and glued into a base for the casting, and doll pins are inserted into the upper portion of the casting. Typically the base is made from yellow stone, and the upper portion of the casting is made from green stone. A lubricant is then applied to the upper portion of the casting.
Recently, a new approach to making these dental castings has been developed, wherein the stone is embedded in a first member, which the first member is retained within a second member. These new systems use armatures disposed on the second member which cooperatively engage an undercut of the first member. The use of these armatures is limiting in that all of the dies must either be engaged or disengaged from the first member. There is no way to disengage only one die while the other dies remain firmly engaged.
In addition, if these new materials are reused for different patients, the accuracy of the dental castings made therefrom will diminish. Typically, the stone used to make the casting degrades over a period of time. As the stone wears, the stone chips and pieces become lodged within the various grooves of these members and are difficult to dislodge.
Also, most impressions are partial, and there may be no need to make a dental casting of an entire jaw. Current state-of-the-art makes no provision for a partial impression, as the patient must endure the discomfort of a full impression, and the dental technician must labor over a full impression when only one or two dies are needed.
Although these new dental casting systems are promising as far as eliminating much of the labor involved in making impressions, these materials are extremely expensive and the reduction in the labor costs are offset by increased equipment expenditures. Dental laboratories must continue to find new labor-saving techniques to reduce their costs, since the costs of labor and materials continue to rise, and it is difficult to pass these increasing costs along to the dentist and the patient.
What is needed is an apparatus to form a dental casting, the apparatus eliminating much of the labor in current techniques, the apparatus using materials that are inexpensive to manufacture, the materials being disposable after a single use, the apparatus enabling a partial impression to be made for the numerous instances when only one or two dies are needed, and the apparatus enabling a single die to be removed therefrom without disengaging neighboring dies therefrom.